Patients may be at risk from a shortage of beds, staff and money that threatens to undermine the most extensive preparation ever undertaken by the NHS, hospital trusts have warned.

With the health service entering its busiest three months of the year, the body that represents hospital, ambulance and mental health trusts says its members will be "sorely tested" this winter despite months of planning.

NHS Providers say hospitals are already severely stretched, with bed occupancy in some trusts running at 98%, and significant delays in transferring patients out of hospital reducing the capacity for new admissions.

Among the measures the NHS and local hospitals have taken to try and ensure safe, high-quality care are:

:: Contingency plans to support trusts facing the greatest pressure

:: Extending the number of GPs "streaming" patients in A&E to reduce strain on emergency departments

:: Local "resilience plans" involving co-operation between health and social care organisations

:: Work to improve the "flow" of patients through hospitals

Image:Bed shortages last year led some patients to be turned away from A&E

Early figures appear to suggest the measures may be working, with the latest figures from Public Health England showing there were no flu-related deaths reported in the week ending 26 November (week 47). Last year, there were 133 deaths over the 26 weeks of the winter - an average of around five a week.

In addition, there were 11 A&E diverts in week 47, compared to 39 in week 46, 10,200 ambulance delays of over 30 minutes, down from 10,600 the week before and the number of bed closures due to Norovirus or Diarrhoea and Vomiting fell slightly from an average of 680 beds to 664 beds closed per day.

Meanwhile, hospital trusts reported bed occupancy levels of 94.5% - up slightly from 94.3% the previous week and there were 274,600 calls offered to the NHS 111 service in the week ending Sunday 3 December, more than the previous week, which had 269,300.

While trusts are hopeful the plans they have put in place will help mitigate some of the issues the health service will face this winter, they say major challenges remain.

Many hospitals privately admit that they have been unable to meet targets to free up bed capacity by discharging more patients ahead of the winter peak, a plan that was supposed to provide an additional 3,700 beds across England.

This increases the prospect of a repeat of last year's difficult winter, when some A&E departments were forced to turn patients away.

The Government provided an additional £350m in the Budget to help the NHS cope with winter, but many believe the money was committed too late to be effectively spent.

"We've now got a system wide plan which involves not just the hospitals in the area but also social services, community services, metal health and primary care. So we've got one big system working together for patients."

The chief executive of NHS Providers, Chris Hopson, said: "Our report highlights the range of measures trusts have put in place to improve resilience and provide safe, timely care for patients.

"But we have to recognise we are not where we would want to be as we head into winter.

"The NHS is already under severe pressure, and while the additional funding in the recent Budget is welcome, it has come very late to be used to maximum effect."

An NHS England spokesperson said: "The NHS has prepared for winter this year more intensely than ever before, developing robust plans to manage expected increased pressures, as well as create contingency plans to cover exceptional surges in demand. The public can continue to play their part by making sure they have their flu jab and by using local pharmacies and NHS 111 for medical advice, alongside other services."